/**
 * Copyright (c) 2009 Mujtaba Hassanpur.
 * 
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 * 
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

import java.util.*;

/**
 * The Randomizer implements the Singleton design pattern to ensure that only
 * one instance of the random number generator is present at any given time.
 * This improves the quality of the random numbers produced.
 */
public class Randomizer extends Random
{
	// required by compiler...
	private static final long serialVersionUID = 5452203260153559973L;
	private static Randomizer generator = null;
	
	/**
	 * The private constructor ensures that only internal methods can construct an instance of
	 * the Randomizer class. This helps in implementing the Singleton design
	 * pattern.
	 */
	private Randomizer()
	{
		// access limited only to internal methods
		super();
	}
	
	/**
	 * This synchronized method is how users of this class will be able to get a reference to
	 * the single instance of the random number generator.
	 * 
	 * @return Returns a reference to the Randomizer instance.
	 */
	public static synchronized Randomizer getGenerator()
	{
		if(generator == null)
		{
			generator = new Randomizer();
		}

		return generator;
	}
}
